Many specific forms of chip control cutting inserts are known in the art including cemented carbide cutting inserts having parallel faces, generally diamond configuration, bottom recesses below the cutting edges and chip breaking walls projecting up from the bottom recess.
U.S. Pat. No. 4,626,141 discloses such insert characterized by a chip control groove extending across polygon insert corners and along edges extending from corners with increasing width away from the cutting corner. The groove is formed with a radius extending below a narrow positive rake cutting edge land to a maximum depth tangent with the bottom of the groove.
The most relevant prior art known to applicants is illustrated in three perspective views of alternative commercial inserts identified in applicants' drawings as PRIOR ART FIGS. 8A-8C.